Sustainable utilization of industrial wastes in controlled low-strength materials: a review

The construction industry is experiencing an increasing demand for sustainable alternative materials. There is huge scope for converting the industrial wastes as partial or complete substitution of cementitious materials and fine aggregates. This study focuses on exploring the performance of different industrial waste materials as possible substitutes for flowable fill or controlled low-strength materials (CLSM). The most commonly used waste materials are found to be bottom ash, pond ash, steel slag, alum sludge, waste glass powder, red mud, cement kiln dust, copper slag, treated oil sand waste, and waste oyster shells. In order to verify their  suitability compaas potential CLSM, the plastic properties (flowability, hardening time, segregation, bleeding, and density), hardened or in situ properties (unconfined compressive strength, California bearing ratio, and ultrasonic pulse velocity), durability properties (permeability and freezing-thawing effects), and microstructural properties (X-ray diffraction and scanning electron microscopy) are compared. It is observed that the addition of different industrial wastes could satisfy the provision of CLSM as per ACI standards. There is immense scope for improvising the present utilization through functional optimization as well as investigating the potential of many unused waste materials which are locally available in bulk.